                            ^:mutable root
                            ^:mutable count]
   Object
-  #_(conj! [tcoll o]
+  (conj! [tcoll o]
     (if edit
       (if (satisfies? IMapEntry o)
         (.assoc! tcoll (key o) (val o))

            node        (-> (if (nil? root)
                              (.-EMPTY BitmapIndexedNode)
                              root)
                            (.inode-assoc nil edit 0 (hash k) k v changed?))]
        (if (identical? node root)
          nil
          (set! root node))

      (throw (js/Error. "count after persistent!"))))

  ITransientCollection
  (-conj! [tcoll val] (.conj! tcoll val))

  (-persistent! [tcoll] (.persistent! tcoll))

